Stocks were in the red and extended losses after Trump's comments. The S&P 500 is down 0.3%. The Nasdaq Composite declined 0.6%.

All three indexes are on track to finish the week lower, and the Dow is looking at a 0.4% weekly loss. By Thursday's close, the S&P and the Nasdaq had retraced their loses from earlier in the week, but the Dow was still lagging behind. Monday was the worst day of the year for the three stock benchmarks.

The 10-year US Treasury yield is tending lower again. The US government bond yield dropped to a three-year low Wednesday as investors bought bonds as a safety investment amid the market turmoil. This change in risk sentiment put pressure on stocks. Yields rebounded Thursday.

On the economic data front, the US producer price index for July advanced 0.2%, in line with expectations and flat at 1.7% on the year. This measure of inflation still tracks below the Federal Reserve's target rate of 2% and reflects a slowing down in manufacturing activity amid weaker global demand.

Equities finished lower down across the board, with Germany's DAX leading losses of more than 1%. Italian bond yields jumped higher, showing that investors aren't confident in Rome resolving its problems. In May 2018, trouble in Italy's government along with worries about the country's financial health and the impact on the European economy triggered a selloff in US stocks.